Long-term swimming and inhaling too much chlorine gas can cause chlorine poisoning, which generally does not cause lung cancer. 1. Chlorine poisoning: patients who inhale too much chlorine gas may have headache, fatigue, cough, loss of appetite, abdominal pain, abdominal distension, and even respiratory difficulties and other symptoms. Specific symptoms lie in the amount of chlorine inhalation, mild poisoning symptoms are relatively light, serious chlorine poisoning patients show more serious symptoms. Patients should stay away from the environment of chlorine gas, and the air environment should be fresh. 2. Inhalation of chlorine gas does not cause lung cancer: there is no authoritative data to prove that chlorine gas is carcinogenic. The causes of lung cancer may be related to smoking, occupational carcinogenic factors, air pollution, ionizing radiation and hereditary factors. Long-term swimmers who inhale chlorine gas too much to appear the above symptoms should actively seek medical attention, so as not to delay the condition, under the guidance of the physician’s interview, in accordance with the standardized treatment, the patient should not blindly take medication.